An example of such semiconductor devices including insulating gate transistors and unipolar diodes is a silicon carbide MOSFET described in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2006-524432. This publication discloses a semiconductor device in which a Schottky barrier diode (SBD) is provided in a chip including a DMOSFET (double diffused MOSFET) made of silicon carbide (SiC). The SBD has a junction barrier Schottky (JBS) structure and has a turn-on-voltage lower than that of a PN body diode included in the DMOSFET.